Self-luminous writing instrument



A. V. T. DAY. SELF LUMINOUS WRITING INSTRUMENT.

APPLICATION HLED SEPT. 25, 1918.

Patented June 20, 1922.

SELF-L'UIVIINOUS 'WRITING INSTRUMENT.

Application filed September 25, 1918.

T 0 all whom it may concern:

Be it known that I, ALBERT V. T. DAY, a citizen of the United States,and residing at New Rochelle, county of lVestchester, and State of NewYork, have conceived certain new and useful inventions embodied in theSelf-Luminous Writing Instrument forth in the following specificationand illus trated in the accompanying drawings.

This invention is a self-luminous writing instrument, to enable the userto write in the dark without the aid of any light extraneous to thedevice itself; and it will be useful also as a lamp of small power forlimited use, for instance to read in the dark by close application ofthe lamp to the text.

One adaptation of the invention is illustrated in the accompanyingdrawings in which:

Figure 1 is a longitudinal view of a selfluminous writing and readingdevice:

Figure 2 is a corresponding enlarged rnidsectional view thereof; and

Figure is a transverse section thereof the plane 33 of Figures 1. and 2.

In this instance the invention is applied to a lead pencil, and in suchmanner that the self-luminous parts may be separated from the writingdevice proper and may be attached. to various devices. Hence. in this aspect, the invention is an attachment for pencils, pens, and the like;but the self-luminous parts may also be manufactured with the rest ofthe writing instrument as a permanent part thereof.

In the illustrated device, a longitudially split spring tube 5 grips thepencil a and carries a longitudinally split spring tube 7 connected tothe pencil tube 5 by solder 6. The spring tube 7 is interiorly threadedto receive the lamp casing 8 screwed into and gripped by it. The lampcasing 8 is cylindrical at its base, and from its base forward it is cutaway on one side to expose the lamp proper, consisting in a glass tube11 closed at its front end by fusion and secured in the casing by thefront lip 13 thereof and a rear plate 12 suitably fastened. The frontend of the lamp bore contains radio-active self- Specification ofLetters ratent.

Patented June 20, 1922.

Serial No. 255,556.

luminous material 10, and its rear end. is sealed by a suitable plug 9,for instance asbestos impregnated with varnish.

The lamp casing will have a light-reflecting inner surface, or the glasslamp tube will be reflectively surfaced under the casing. In eitherevent the light will be reflected from one side of the lamp tube towardthe other side presented to the writing paper or other surface to beillumined, and the reflecting side of the lamp will screen theself-luminous material from view of the user, to avoid confusing thevision by its relative brightness in direct view. The lamp bore may beflat, as indicator, presenting one flat side toward the reflector. andthe other toward the direction of illumination. The self-luminous material will preferably be in loose powder form, and will itself betranslucent or transparent so as to transmit light disseminated from allits interior particles, and retransmit its own rays passing into it fromthe reflector.

The longitudinal and angular positions of the lamp on, the pencil areadjustable by shifting the pencil tube on the pencil and by turning thelamp casing in the lamp tube '7.

The invention comprehends all adaptations within the definitions of thefollowing claims: I

i. A selfduminous writing instrument comprising a marking device and aselfluminous body secured thereon at one side of the axis of the markingdevice and near its marking point, and rotatable screen secured at oneside of the self-luininous body.

2. A self-luminous writing instrument comprising a marking device and aselfluminous body longitudinally adjustable thereon in general positionnear the marking point of said device and at one side of its axis, and ascreen adapted to screen said self-luminous body on one side androtatably adjustable about it.

In testimony whereof, I have affixed my signature to this specification.

ALBERT V. T. DAY.

